If his fellow Republican senators were more like him, it might not even be an issue.

And yet, it may become the single largest hurdle to his reelection.

That matter?

This simple reality: His reelection could put the GOP in control of the US Senate.

If so, his victory would make Mitch McConnell the next majority leader. McConnell, now minority leader, has dedicated himself to using the filibuster to obstruct President Obama in the hopes of defeating him.

It’s an argument Democrats will be hitting hard between now and election day.

“I don’t think any of us are willing to see President Obama raise his right hand to be inaugurated in January just so that inside the Capitol, a majority leader, McConnell, can raise his right hand to stop everything that he has pledged and wants to do,” Senator John Kerry said as he stood beside Warren at a Monday press conference.

Building on an argument Warren herself has started to make, Kerry stressed that giving the Republican Party control of the US Senate will mean giving Jim Inhofe of Oklahoma, a climate-change denier, control over the Environment and Public Works Committee. It would put an anti-abortion-rights senator in control of the Judiciary Committee, which plays a crucial role in confirming federal judges, he said, and hand the Finance Committee to a party determined to repeal Obamacare and make the Bush tax cuts for upper earners permanent.

It would also put the Commerce Committee under the control of Jim DeMint, a Tea Party partisan from South Carolina; and give the banking panel gavel to someone opposed to the Dodd-Frank financial-reform law. Further, he noted, the Senate would be run by a party whose members, including Brown, have taken Grover Norquist’s No New Taxes pledge, which precludes a balanced approach to deficit reduction.

Kerry understands the potency of this issue. In 1996, it helped him turn back Bill Weld. Although popular, accomplished, and well-financed, Weld was knocked off-balance by the question of whether, as a Republican senator, he would be a vote for reconfirming Jesse Helms, then an arch-conservative GOP senator from North Carolina, as chairman of the Senate Foreign Relations Committee. Queried on that in the final campaign debate, Weld hemmed and hawed, saying he would “have to wait and see.”

“Massachusetts . . . decided Bill Weld was a great guy, but [one] whose first vote in the United States Senate would do very bad things for Massachusetts,” Kerry recalled. “Because that’s the vote that chooses a majority leader, and it creates the chairmen whose work hurts or helps every single thing that we care about in our state.”

That’s a hard argument to handle, though Brown’s team is trying.

“It sounds like the race Professor Warren has isn’t the one she wants,” said spokeswoman Alleigh Marre. “She’s running against Scott Brown, who is the second-most bipartisan senator.”

That’s true. Yet the determined obstructionism of Brown’s fellow Republicans in the Senate makes this about more than his individual inclination toward bipartisanship.

“There is some power to the argument that you will be part of the glue in the center, but the strategy Mitch McConnell has pursued is a strategy of filibustering anything and everything,” says Norm Ornstein, congressional scholar at the American Enterprise Institute. “Unless you are willing to denounce that strategy and say you will not join in that kind of filibuster, then the argument that you are not tied to the Republican brand just loses its strength.”

Although Brown has occasionally voted to end GOP filibusters, he has shown little interest in leading, or even joining, an effort to curtail filibuster abuse. Nor has he taken the simple move of announcing that he himself will routinely vote against filibusters and in favor of bringing issues to the Senate floor for debate on the merits.

Now he’s left fighting the same political current that undercut Weld’s Senate hopes in 1996 and washed Rhode Island’s Lincoln Chafee, another popular New England Republican, out of the Senate a decade later.

And in this pivotal race, in these polarized times, that current could well become a rip-tide.

Scot Lehigh can be reached at lehigh@globe.com. Follow him on twitter at @GlobeScotLehigh.

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